Pharmaceutical composition containing heparin, heparin fragments or their derivatives in combination with glycerol esters

ABSTRACT

The present invention relates to pharmaceutical compositions containing heparin or heparin fragments or their derivatives in combination with one or more glycerol esters of at least one fatty acid as single absorption enhancer. The compositions are useful for oral administration, for administration through mucous membranes or for transdermal administration. The compositions will when necessary contain further physiologically acceptable additives, such as diluents and/or carriers, suitable for the adaptation to oral, buccal, rectal, sublingual, nasal, subcutaneous or transdermal administration. The composition according to the invention provide excellent absorption and bioavailability without employing additional enhancers or promoters.

INTRODUCTION

This application is the national phase of PCT/SE94/00595, filed Jun. 16,1994.

The present invention relates to pharmaceutical compositions containingheparin or heparin fragments or their derivatives in combination withone or more glycerol esters of at least one fatty add as singleabsorption enhancer. The compositions are useful for oraladministration, for administration through mucous membranes or fortransdermal administration. The compositions will when necessary containfurther physiologically acceptable additives, such as diluents and/orcarriers, suitable for the adaptation to oral, buccal, rectal,sublingual, nasal, subcutaneous or transdermal administration. Thecompositions according to the invention provides excellent absorptionand bioavailability without employing additional enhancers or promoters.

BACKGROUND OF THE INVENTION

Heparin is a sulphate-containing polysaccharide widely used as ananti-coagulant, which originates from the intestinal mucosa of swine orlungs from cattles. It has been used for decades for the treatment andprevention of thrombosis. In recent years several new generations ofheparin derivatives and fragments with more efficient and specificactivity have been developed and marketed. Such low molecular fragmentsof heparin are disclosed e.g. in EP-A-0 014 184. The product, known asFragmin®, is marketed by Pharmacia AB of Stockholm, Sweden.

It has been a considerable problem to find alternative administrationroutes to injections for all heparins and their fragments due to theirpoor absorbability, for example when administered orally or rectally. Asafe and efficient alternative to injections is therefore demanded forincreasing the convenience for patients subjected to long-term treatmentwith heparins or heparin fragments.

There are several disclosures of pharmaceutical systems for enhancingthe penetration of heparins or low molecular weight derivatives thereofthrough body membranes. Different rectal or enteral compositions aredescribed in the patent specifications U.S. Pat. No. 4,156,719, DE-A-3331 009 and EP-A-0 037 943. In these disclosures the bioabsorption isenhanced by means of various surface active agents or by carboxylic addssuch as salicylic acid and glutamic acid. Compositions containingsulfones and fatty alcohols for oral, buccal and sublingualadministration of heparin are described in U.S. Pat. No. 3,510,561.WO-A-88/10117 relates to an oral heparin composition containing amonosaccharide and a salt of a metallic cation. EP-A-0 130 555 disclosespharmaceuticals containing heparins and non-ionic tensides with improvedpermeability in the mouth and the nose.

However, none of these disclosed compositions have successfully led toproducts which substitute parenteral administration of heparins orheparin fragments.

It is the object of the present invention to provide new compositionscontaining therapeutically effective amounts of heparin, heparinfragments or their derivatives, which have a bioavailability high enoughto result in clinically relevant plasma levels, when administered orallyor through mucous membranes or through the skin, comparable to thoseobtained from a subcutaneous or intramuscular injection. According tothe present invention such compositions are conceivable by using heparinin combination with one or several glycerol esters of fatty adds in apharmaceutical composition. Medium chain glycerides have previously beenused as absorption enhancers both in rectal and topical compositions,but only successfully when smaller molecules and certain polypeptidessuch as calcitonin and insulin are used in the system, and in mostapplications together with additional enhancing vehicles, such assurface active agents. There are currently no successful compositions interms of improved biological absorption with larger therapeuticallyuseful hydrophilic polysaccharides (such as heparins and theirfragments) with glycerides of fatty adds as absorption enhancingcomponents.

DESCRIPTION OF THE INVENTION

The invention is generally related to a composition of a therapeuticallyeffective amount of a heparin and/or heparin fragments and/orderivatives thereof and at least one glycerol ester of one or severalfatty acids, a method for the manufacture of such a composition, the useof the composition for the manufacture of medical preparations and theuse of glycerol esters of one or several fatty acids for enhancing theabsorption of heparins through body membranes.

According to this invention the expression "a heparin" or "heparins"denotes any fraction or class of heparin from natural, biosynthetic orgenetically engineered source, as well as any derivative thereof e.g.heparin esters. A fragment of heparin denotes any low molecular weightfragment of heparin or their derivatives having heparin activityincluding chemically modified, biosynthetic, semi-synthetic or syntheticheparin-like oligosaccharides. Suitably, the low molecular weightheparin fragments and/or their derivatives, have a molecular mass in therange of from about 1000 to 10000 Dalton.

A heparin fragment preferred according to the present invention isFragmin®, which is, as mentioned above, disclosed in EP-A-0 014 184. TheFragmin® may be in the form of a solution or a suspension when added toor mixed with the other components of the composition. It can also beadmixed as a powder or in a solution with an essentially water-fleelipid matrix consisting of the mentioned glycerides. Fragmin® is veryreadily soluble in water and such aqueous compositions are considered tohave excellent stability. The solubility and stability of Fragmin®facilitates the adaption of the composition to a suitable administrationform.

The glycerol esters of fatty acids according to the present inventionare mono; di- or triglycerides or any mixtures thereof, of at least onefatty acid. The fatty acid residues can be the same or vary on the di-and tri-glyceride molecules. For a mixed population of mono-, di- andtriglycerides the acyl groups or fatty acid residues can be the same ordifferent in each category of molecule. Suitably, the acyl groups arecarefully defined, preferably with a chain length of between 6 and 18carbon atoms. The choice of relative composition of such mono-, di- ortriglycerides in a composition according to the invention will depend onthe actual administration route. Furthermore, the choice of the relativecomposition of such mono-, di- or triglycerides may be used as a deviceto control absorption rate and/or the release rate of the heparins, asthe glycerides can differ both in chain length, in polarity, in thedegree of unsaturation and in other physical properties such as meltingpoint and viscosity. Another suitable way to control the absorptionand/or release rate of the heparins or their fragments is to vary thechain lengths of the acyl groups between 6 and 18 carbon atoms.

The properties of the composition containing heparins and glycerideesters of fatty acids will thus be influenced by the polarity, the chainlengths, the relative amounts of the constituents and the number ofunsaturated bonds in the acyl groups of the glycerides.

Anyone skilled in the art will readily find suitable components foradapting the composition to an advantageous delivery system fortherapeutically effective amounts of heparins, by varying the lipidconstituents, for example by varying the choice of lipid start material,thereby obtaining compositions with different viscosity and absorptionenhancing capacity.

A composition which is preferred according to the present invention willcontain monoglycerides with defined acyl groups within the range of 6 to18 carbon atoms. Suitable monoglycerides will essentially consist of amixture of 8:0 caprylate and 10:0 caprate. Such compositions are veryflexible in that they may easily be adapted to a variety of preparationsfitting each desired administration route by adding suitable excipients.

Tests with heparin compositions containing triglycerides, also showimproved absorption performance. The use of triglycerides isadvantageous, since normally triglycerides are cheaper than both mono-and diglycerides. However, the concentration required to obtain enhancedabsorption while at the same time avoiding a toxic effect may be higherwith triglycerides than with mono- and/or diglycerides.

The preparation of the compositions according to the present inventioncan be performed in different manners, which are chosen with respect tothe intended administration route. For example, when Fragmin® is to bemixed to a homogenous composition with the lipid component orcomponents, it can be present as a powder, which is dispersed in thelipids, as solution with an excess amount of water to be admixed withthe lipids or as solution which after mixing with the lipids provides anessentially water-free matrix composition. The flexibility and stabilityof Fragmin® makes it easy to adapt for any desired composition, such asa solution, a suspension or any semi-solid, viscous or solid matrix thatis required for a specific administration form and for the specificquality of the glyceride component, for example in terms of viscosityand absorption enhancing properties.

Preparations can be adapted for rectal use in the form of foams,clysmas, capsules and suppositories or different preparations speciallymanufactured for oral, buccal, sublingual, nasal, transdermal andsubcutaneous administration or for administration through mucousmembranes in general. The inventive compositions containing heparins,their fragments or derivatives and glycerol esters of fatty acids arealso suitable for the manufacture of a depot preparation for obtainingcontrolled release for e.g. subcutaneous administration or forcontrolled oral release by applying enclosing barrier membranes to theoral dosage forms. Another suitable preparation according to theinvention are buccal dosage forms where the inventive composition isapplied to a porous polymeric matrice or enclosed within an envelopeoptionally with mucoadhesive properties. The mentioned preparations areuseful for treating and/or preventing a wide variety of pathologicalprocesses commonly associated with heparin therapy such asthromboembolic diseases, preinfarctional angina, coronary heartdiseases, inflammatory diseases, thrombophlebitis, autoimmune diseases,arteriosclerosis or for treatment of metha-sthasis or angiogenesisrelated diseases. Every adaptation in terms of finding the appropriateexcipients or vehicles for the compositions for the above-mentionedadministration routes for treatments associated with heparins or theirfragments will be obvious to persons skilled in this art.

The total dosage of the heparins or heparin fragments in theabove-mentioned administration forms can thus be very high and islimited only by the bioavailability and by that which is therapeuticallyor clinically appropriate to administer and well tolerated. Examples ofclinical doses of Fragmin® are 120 IU per kg body weight twice daily fordeep venous thrombosis and for thrombosis prophylaxis 2500 IU per day(for low risk patients) or 5000 IU per day (for high risk patients). Forexample, the relative amount of Fragmin® to the lipids containingglycerol esters of fatty acids can be in the range of preferably 1-200%(w/w). However, a higher amount of either Fragmin® or lipids areconceivable within the context of the invention, if it is clinicallysuitable. If the amount of lipids will be too low in a composition theenhanced absorption effect will be reduced, which may be compensated byan increased amount of Fragmin, in order to obtain the same serum levelsafter administration or vice versa. This broad concentration range,which makes it possible to have Fragmin® to lipid in a relative amountof up to 200% (w/w), indicates the flexibility of the components whichreadily can be adapted to a composition for suitable dosage forms to bedelivered to different types of patients.

The following examples show the bioavailability and the absorption of acomposition according to the invention containing Fragmin® and definedmonoglycerides. The compositions have been administered rectally andintraduodenally to rabbits in-vivo. The examples are not intended tolimit the scope of invention, only to illustrate a special embodimentaccording to the invention. Example 1 shows the constituents of thedefined monoglyceride used in the following examples. Example 2 showsintraduodenal and rectal absorption, respectively for a Fragmin® and themonoglyceride composition according to Example 1. Example 3 is acomparative example showing the bioavailability of intraduodenally orrectally applied Fragmin® without the monoglycerides.

The results show unambiguously that Fragmin® in this application has anabsorption which result in a plasma level at least comparable to e.g.subcutaneous administration. It is surprising that no other penetrationenhancer or enhancers including surface active agents or othercomponents are necessary to achieve a favourable bioavailability andabsorption. Furthermore, it is surprising that the monoglyceride is soeffective, even in low concentrations, which indicate uniqueopportunities for new administration forms and/or routes and possiblyalso a specific synergistic interaction between the involved componentsand cellular constituents.

EXAMPLE 1

The monoglyceride used in the following examples was a highly purifiedfraction supplied by Karlshamns LipidTeknik AB, Sweden with thefollowing composition:

    ______________________________________                                               8:0 caprylate                                                                         78.4                                                                  10:0 caprate                                                                          21.2                                                                  12:0 laurate                                                                          0.2                                                                   minors  0.2                                                                   Total   100                                                            ______________________________________                                    

EXAMPLE 2

The animal model

Male New Zealand white rabbits, weighing 2.5 kg to 3.5 kg were used inall experiments. After fasting for 12 hours, each animal was sedatedwith an intramuscular injection of Hypnorm 0.1 ml/kg (JanssenPharmaceuticals, Belgium) and a subcutaneous injection of Atropine 0.5ml/kg (Pharmacia, Sweden). The rabbits were anaesthetized with Mebumal20 mg/m. The anaesthesia was subsequently maintained when needed. Theanimals were shaved and a medical laparotomy were performed. The testcompound was then injected directly into the duodenum and the peritonealcavity was thereafter closed. The dose was checked by weighing thesyringe before and after administration of the test compound. Bloodsamples of 1.5 ml were collected after 0.0, 0.25, 0.5, 1.0, 1.5, 2.0,2.5, 3.0, 3.5, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0 and 10.0 hours from acatheter positioned in the ear artery. The samples were mixed withsodium citrate to a final concentration of 0.04M. The sample tubes werekept on ice until they were subjected to a centrifugation procedure(3500 rpm for 5 minutes). The anti-FXa activity in plasma was determinedby an initial rate assay using bovine FXa (Pharmacia) and thechromogenic substrate S-2222. This animal model was utilized in thefollowing experiments with intraduodenally and rectally applied Fragmin®and monoglycerides.

Intraduodenal absorption of Fragmin® and glycerides

The bioavailability of Fragmin® after an intraduodenal administration isexpressed as a fraction of the area under the anti-FXa activity curvei.e. (AUC id) and (AUC sc), the latter determined to be 5.14±0.34arbitrary units in 6 rabbits receiving a subcutaneous injection ofFragmin at a dose of 2 mg/kg. The intraduodenal absorption of Fragmin®mixed with monoglycerides according to Example 1 was tested in 5rabbits. Fragmin® powder was dissolved in physiological saline to afinal concentration of 50 mg/ml (5.0%). Four parts per weight of thisFragmin® solution were mixed with one part (weight) of monoglyceride,approximately 15 hours prior to the experiment. All rabbits received thefollowing doses: Fragmin 25 mg/kg, monoglyceride 0.125 g/kg and saline0.5 ml/kg. All rabbits in this experiment had detectable levels ofanti-FXa activity in plasma. The maximal plasma concentration (C_(max))was reached within 0.5-3.0 hours and ranged between 3.30 IU/ml and 4.70IU/ml. The average absorption was 25.0±9.0% of subcutaneous injection.

Rectal absorption of Fragmin® glycerides

The rectal absorption of Fragmin® mixed with the highly purifiedmonoglyceride according to Example 1, essentially composed of 8:0caprylate and 10:0 caprate, was tested in five rabbits. The Fragmin®,manufactured by Pharmacia AB, was dissolved in physiological saline to afinal concentration of 10 mg/ml. This solution was mixed with fiemonoglyceride (final concentration 250 mg/ml) by vigorous shaking untilfie dispersion appeared homogeneous. The Fragmin®/monoglyceridecomposition was injected directly into the rectum at a volume of 0.5-0.6ml depending on the weight of fie rabbit. This corresponds to a dose of2 mg/kg and 50 mg/kg for Fragmin® and the monoglyceride, respectively.All rabbits showed high levels of anti-FXa activity in plasma. C_(max)was reached within 1.5-2 hours and ranged between 1.85 IU/ml to 2.56IU/ml. The area under the curve (AUC) was 6.56±1.54 which is 1.3 timeshigher than the AUC after a subcutaneous injection. This indicates thatrectal absorption of Fragmin® is similar or slightly higher than thebioavailability after a subcutaneous administration.

EXAMPLE 3

Bioavailability of Fragmin® in the absence of glycerides

The bioavailability of Fragmin® after an intraduodenal administration inthe absence of the monoglycerides of Examples 1-2 was tested in 4rabbits. Two of the rabbits received Fragmin®, 25 mg/kg, as a powderincluded in a gelatine capsule which was placed in the duodenum at thepylorus level The remaining two rabbits received Fragmin® dissolved inphysiological saline, which was injected directly into the duodenum(total dosage 25 mg/kg). No anti-FXa activity could be detected in anyof these animals over an observation period of 8-10 hours. Thebioavailability of Fragmin® after a rectal administration was tested in3 rabbits. Fragmin® was dissolved in physiological saline and injecteddirectly into the rectum at a dosage of 10 mg/kg. Two of these rabbitshad no detectable anti-FXa activity in plasma but one showed an activityof 0.2 IU/ml for 45 minutes which corresponds to a bioavailability ofless than 1%. The conclusion is that the bioavailability of Fragmin® inthe absence of the monoglyceride is less than 1% after an intraduodenalor a rectal administration.

I claim:
 1. A homogenous composition comprising:(i) a therapeuticallyeffective amount of at least one compound selected from the groupconsisting of heparin, heparin fragments and their derivatives, and (ii)as the absorption enhancer, a monoglyceride having acyl consistingessentially of a mixture of the fatty acids 8:0 caprylate and 10:0caprate.
 2. A composition according to claim 1 further comprising atleast one additional physiologically acceptable additive, suitable fororal, rectal, buccal, nasal, sublingual, subcutaneous or transdermaladministration.
 3. A composition according to claim 2 wherein saidadditive is a diluent, carrier or both.
 4. A composition according toclaim 1 wherein said at least one compound comprises low molecularweight heparin fragments or their derivatives, or both, with a meanmolecular mass of about 1000 to 10000 Dalton.
 5. Oral preparationcomprising a composition according to claim 1 optionally provided withrelease controlling membrane.
 6. Buccal preparation comprising acomposition according to claim
 1. 7. A preparation for administrationthrough mucous membranes comprising the composition according toclaim
 1. 8. Method for manufacturing the composition according to claim1, which comprises mixing a powder and an aqueous solution or suspensionof the heparin or the heparin fragment or derivative with saidmonoglyceride to form a homogenous composition.
 9. A compositionaccording to claim 2 wherein said at least one compound comprises lowmolecular weight heparin fragments or their derivatives, or both, with amean molecular mass of about 1000 to 10000 Dalton.
 10. A compositionaccording to claim 3 wherein said at least one compound comprises lowmolecular weight heparin fragments or their derivatives, or both, with amean molecular mass of about 1000 to 10000 Dalton.
 11. Oral preparationcomprising a composition according to claim 2 optionally provided withrelease controlling membrane.
 12. Oral preparation comprising acomposition according to claim 3 optionally provided with releasecontrolling membrane.
 13. Oral preparation comprising a compositionaccording to claim 4 optionally provided with release controllingmembrane.
 14. Buccal preparation comprising a composition according toclaim
 2. 15. Buccal preparation comprising a composition according toclaim
 3. 16. Buccal preparation comprising a composition according toclaim
 4. 17. A preparation for administration through mucous membranescomprising the composition according to claim
 3. 18. A preparation foradministration through mucous membranes comprising the compositionaccording to claim
 4. 19. Method for manufacturing the compositionaccording to claim 3, which comprises mixing a powder and an aqueoussolution or suspension of the heparin or the heparin fragment orderivative with said monoglyceride to form a homogenous composition. 20.Method for manufacturing the composition according to claim 4 whichcomprises mixing a powder and an aqueous solution or suspension of theheparin or the heparin fragment or derivative with said monoglyceride toform a homogenous composition.